Senate Majority Leader Harry Reid took his GOP-blasting rhetoric to a new level Monday, comparing Republicans who oppose health care reform to lawmakers who clung to the institution of slavery more than a century ago.

The Nevada Democrat, in a sweeping set of accusations on the Senate floor, also compared health care foes to those who opposed women's suffrage and the civil rights movement -- even though it was Sen. Strom Thurmond, then a Democrat, who unsuccessfully tried to filibuster the Civil Rights Act of 1957 and it was Republicans who led the charge against slavery.

Senate Republicans on Monday called Reid's comments "offensive" and "unbelievable."

But Reid argued that Republicans are using the same stalling tactics employed in the pre-Civil War era.

"Instead of joining us on the right side of history, all the Republicans can come up with is, 'slow down, stop everything, let's start over.' If you think you've heard these same excuses before, you're right," Reid said Monday. "When this country belatedly recognized the wrongs of slavery, there were those who dug in their heels and said 'slow down, it's too early, things aren't bad enough.'"

He continued: "When women spoke up for the right to speak up, they wanted to vote, some insisted they simply, slow down, there will be a better day to do that, today isn't quite right.

"When this body was on the verge of guaranteeing equal civil rights to everyone regardless of the color of their skin, some senators resorted to the same filibuster threats that we hear today."

That seemed to be a reference to Thurmond's famous 1957 filibuster -- the late senator switched parties several years later.

Reid's office stood by the remarks, with spokesman Jim Manley saying Republicans have "done nothing but obstruct health care" in the Senate.

"Today's feigned outrage is nothing but a ploy to distract from the fact they have no plan to lower the cost of health care, stop insurance company abuses or protect Medicare," Manley said.

But Republicans said they were genuinely appalled. Sen. Orrin Hatch, R-Utah, said Reid's remarks were over the top.

"That is extremely offensive," he told Fox News. "It's language that should never be used, never be used. ... Those days are not here now."

Sen. John McCain, R-Ariz., who on the Senate floor read from this FoxNews.com article and asked that it be placed in the record, called on Reid to return to the floor and, if not apologize, at least explain what he meant.

Sen. Saxby Chambliss, R-Ga., suggested Reid was starting to "crack" under the pressure of the health care reform debate.